This invention relates to an electrostatic device for the gating of electromagnetic radiation having a resilient variable electrode. An insulative film is bonded to either a fixed or the variable electrodes so as to provide electrical insulation between the two electrodes. In some prior devices of this kind the variable electrode is mounted to the fixed electrode. It is particularly difficult in such structures to provide a mounting of the fixed electrode that does not induce wrinkles in the thin resilient electrode. When the mounting of the variable electrode is spaced from the fixed electrode and the variable electrode is straight in this space, the wrinkles emanating from the mounting are attenuated but still remain a source of variability in sensitivity. In either case much care is required in the mounting of the resilient variable electrode to minimize the wrinkles that tend to be formed there. Examples of prior art devices of the improved kind are described in U.S. Pat. No. 3,897,997 issued Aug. 5, 1975.
Such wrinkles tend to radiate away from the mounting and make the variable electrode stiffer. This in turn raises the sensitivity of the light gate to an electrical signal that is applied between the two electrodes to cause the variable electrode to be drawn to and become coadunate with the fixed electrode. Furthermore, in manufacturing a large number of such devices the sensitivity of the devices from unit to unit is not uniform.
It is therefore an object of this invention to provide an electrostatic gating device having a low sensitivity to an applied electrical signal by eliminating wrinkles in the variable electrode.
It is a further object of this invention to provide an electrostatic light gate having a more uniform and predictable sensitivity to an applied electrical signal.
It is a further object of this invention to provide an electrostatic light gate capable of being assembled in a simple noncritical manner.